package org.codingeasy.streamrecord.core.utils;

import org.springframework.aop.framework.AdvisedSupport;
import org.springframework.aop.framework.AopProxy;
import org.springframework.aop.support.AopUtils;

import java.lang.reflect.Field;

/**
 * @author : KangNing Hu
 */
public class ProxyUtils {


  /**
   * 获取 目标对象
   *
   * @param proxy 代理对象
   */
  public static Object getTarget(Object proxy) {
    try {
      if (!AopUtils.isAopProxy(proxy)) {
        return proxy;//不是代理对象
      }

      if (AopUtils.isJdkDynamicProxy(proxy)) {
        return getJdkDynamicProxyTargetObject(proxy);
      } else { //cglib
        return getCglibProxyTargetObject(proxy);
      }
    } catch (Exception e) {
      throw new IllegalStateException(e);
    }
  }

  /**
   * 获取cglib的代理类
   */
  private static Object getCglibProxyTargetObject(Object proxy) throws Exception {
    Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0");
    h.setAccessible(true);
    Object dynamicAdvisedInterceptor = h.get(proxy);

    Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");
    advised.setAccessible(true);

    return ((AdvisedSupport) advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();
  }


  /**
   * 获取jdk代理的目标类
   */
  private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception {
    Field h = proxy.getClass().getSuperclass().getDeclaredField("h");
    h.setAccessible(true);
    AopProxy aopProxy = (AopProxy) h.get(proxy);

    Field advised = aopProxy.getClass().getDeclaredField("advised");
    advised.setAccessible(true);

    return ((AdvisedSupport) advised.get(aopProxy)).getTargetSource().getTarget();
  }
}
